Manufacturing method and manufacturing apparatus for an optical data recording medium, and an optical data recording medium

Abstract

A manufacturing method for an optical data recording medium having a substrate with at least one signal recording layer and a resin layer for passing light, the manufacturing method includes: coating a radiation-curable resin on the substrate; and forming the resin layer by curing at least a part of the radiation-curable resin by increasing the rotational speed of the substrate to a first speed, then decreasing the rotational speed of the substrate, and emitting radiation while the rotational speed of the substrate is decreasing.

1 . A manufacturing method for an optical data recording medium having a substrate with at least one signal recording layer and a resin layer for passing light, the method comprising: 
 coating a radiation-curable resin on the substrate; and    forming the resin layer by curing at least a part of the radiation-curable resin by increasing the rotational speed of the substrate to a first speed, then decreasing the rotational speed of the substrate, and emitting radiation while the rotational speed of the substrate is decreasing.    
     
     
         2 . The optical data recording medium manufacturing method according to  claim 1 , wherein the step of forming the resin layer forms the resin layer by curing at least a part of the radiation-curable resin by emitting radiation after the rotational speed of the substrate reaches a second speed that is lower than the first speed.  
     
     
         3 . The optical data recording medium manufacturing method according to  claim 2 , wherein the step of forming the resin layer forms the resin layer by curing at least a part of the radiation-curable resin by emitting radiation while rotating the substrate at the second speed for a predetermined time.  
     
     
         4 . The optical data recording medium manufacturing method according to  claim 1 , wherein the step of forming the resin layer forms the resin layer by curing at least a part of the radiation-curable resin by emitting radiation to the substrate through a light shielding mask, 
 the light shielding mask having a round hole with an inside diameter equal to or less than the outside diameter of the substrate, and disposed with this hole in the light shielding mask concentric to the substrate.    
     
     
         5 . The optical data recording medium manufacturing method according to  claim 4 , further comprising: 
 spinning off radiation-curable resin at the outside edge part of the substrate after the step of forming the resin layer by accelerating the rotational speed of the substrate to a predetermined speed that is higher than the first speed.    
     
     
         6 . The optical data recording medium manufacturing method according to  claim 5 , further comprising: 
 emitting radiation to the outside edge part of the substrate to cure the radiation-curable resin at the outside edge part of the substrate after the step of spinning off the radiation-curable resin at the outside edge part of the substrate.    
     
     
         7 . The optical data recording medium manufacturing method according to  claim 1 , wherein the step of coating the radiation-curable resin uses a spin coating method.  
     
     
         8 . The optical data recording medium manufacturing method according to  claim 1 , wherein the step of coating the radiation-curable resin uses a substrate with a center hole, and covers the center hole to coat the radiation-curable resin on the substrate.  
     
     
         9 . The optical data recording medium manufacturing method according to  claim 1 , wherein the resin layer is a light transmitting layer rendered on top of a signal recording layer.  
     
     
         10 . The optical data recording medium manufacturing method according to  claim 1 , wherein the resin layer is a protective layer.  
     
     
         11 . The optical data recording medium manufacturing method according to  claim 1 , wherein the resin layer is an intermediate layer rendered between a plurality of signal recording layers.  
     
     
         12 . The optical data recording medium manufacturing method according to  claim 11 , further comprising: 
 forming an intermediate layer by applying a stamper having a pattern of grooves or pits and lands to the at least partly cured radiation-curable resin on the substrate, and then emitting radiation to cure the uncured resin after the step of forming the resin layer.    
     
     
         13 . A manufacturing apparatus for an optical data recording medium, comprising: 
 a rotating table operable to rotatably hold a substrate coated with a radiation-curable resin;    a motor operable to rotate the rotating table;    a radiation lamp operable to emit radiation to the radiation-curable resin on the substrate to cure at least a part of the radiation-curable resin; and    a control unit operable to control the speed of the motor and the emission timing of the radiation lamp.    
     
     
         14 . The optical data recording medium manufacturing apparatus according to  claim 13 , further comprising: 
 a light shielding mask having a round hole with an inside diameter equal to or less than the outside diameter of the substrate, the light shielding mask disposed between the substrate and the radiation lamp without contacting the substrate and with the hole in the light shielding mask concentric to the substrate as seen from the radiation lamp;    wherein radiation is emitted from the radiation lamp through the light shielding mask to the substrate.    
     
     
         15 . The optical data recording medium manufacturing apparatus according to  claim 13 , wherein: 
 the control unit increases the speed of the motor to a first speed, then decreases the speed, and emits radiation from the radiation lamp to the radiation-curable resin on the substrate while the speed is decreasing.    
     
     
         16 . The optical data recording medium manufacturing apparatus according to  claim 13 , wherein: 
 the control unit increases the speed of the motor to a first speed, then decreases the speed, and after the motor reaches a second speed that is lower than the first speed emits radiation from the radiation lamp.    
     
     
         17 . An optical data recording medium manufactured by the manufacturing method according to  claim 1 , wherein: 
 the resin layer thickness near the outside edge part of the substrate is 10 μm or more thinner than the average thickness of the entire resin layer on the substrate.